This invention relates to the recovery of glass from municipal waste and trash, and is particularly concerned with procedure for recovery of a fine glass product from municipal waste, which can be used in various industrial applications; and to the novel fine glass product thus recovered in the process.
The prior art heretofore has been essentially concerned with recovery of coarse glass from municipal waste or trash. Such coarse grades of glass, and the degree of impurity thereof, have not permitted this type of glass to be employed in many industrial applications, and such coarse and impure grades of glass particularly are not suited for recycle to glass manufacture.
Thus, it is known to shred municipal waste containing glass, and to subject the shredded material to air classification for separation of an overhead or lighter material from the heavier material which falls in the air classifier. Such heavier materials include coarse or large pieces of glass, as well as pieces of metals, rocks and wood. The heavy materials including coarse glass comprising pieces of the order of about 1/4 inch to 1 inch in size is then fed to an air table to remove organics such as plastics, rags, heavy paper and the like, and to separate the heavier materials into a glass product comprised of the above-noted coarse glass pieces, the glass product recovered being of a size and degree of impurity unsuitable for use in many industrial applications, or for recycle to glass manufacture, without further substantial and costly processing.
As previously noted, a substantial need has now developed for the recovery of glass from municipal waste and trash in the form of fine glass of substantially reduced organic content and improved purity, for use in industrial applications such as in slurry seal, as a brick additive, in composition resin-glass panels, and the like, and particularly of a grade which by further beneficiation is of sufficient purity for recycle to glass manufacture. Accordingly, it is a particular object of the present invention to produce such fine and relatively higher grade glass product from municipal trash and waste.